CA Water Forecast Improvement Driven by NOAA Innovation and Partnerships

The National Oceanic and Atmospheric Administration’s (NOAA) Physical Sciences Division (PSD) is entering its third consecutive five-year Memorandum of Understanding (MOU) with the California Department of Water Resources (CA-DWR) as part of the Enhanced Flood Response and Emergency Preparedness (EFREP) program. The cornerstone of these MOUs has been the development, deployment, operation, and maintenance of a 21st-century observing system to help California deal with its water resource and flood protection issues.

PSD has installed six coastal and inland atmospheric river observatories (AROs) to provide key observations of these narrow regions of enhanced water vapor transport (a.k.a. atmospheric rivers, or ARs) as they make landfall and produce enhanced precipitation, especially in the coastal mountains and the Sierra Nevadas.

The increased understanding of ARs and their impacts provided by the AROs and research conducted by PSD and its partners have improved situational awareness in National Weather Service (NWS) forecast offices, which has allowed California and the U.S. Army Corps of Engineers to better manage water resources through the practice of forecast improved reservoir operations (FIRO).

A network of 52 GPS receivers, many of which were already in place for geodetic purposes, monitors the inland transport of total precipitable water in ARs to determine which watersheds will be vulnerable to enhanced precipitation that could lead to flooding. A network of ten snow-level radars, a technology invented by PSD engineers specifically for this project, monitors the level in the atmosphere where snow changes into rain, a critical parameter for predicting runoff in mountainous watersheds. A network of 40 soil moisture stations was installed to monitor this important variable.

More recently, PSD is leading a collaborative project with other federal laboratories, cooperative institutes, and local water agencies in the San Francisco Bay Area to improve monitoring and prediction of precipitation, streamflow, and coastal flooding for this heavily populated region. This project will install five precipitation scanning radars in the Bay Area and will provide high-resolution weather forecasts and output from a coastal flooding and inundation model to improve water management and warnings to the public about flooding. The project, called Advanced Quantitative Precipitation Information (AQPI), is managed locally by Sonoma Water.

The EFREP and AQPI projects serve as templates for hydrometeorology projects that could be conducted in other regions around the world where water management is critical.